Manual mixer

ABSTRACT

A manual mixer serves to facilitate mixing and agitating materials for use during surgery. For example, the manual mixer includes a body portion defining an interior area, a mixing assembly provided in the interior area of the body portion, a crank assembly for actuating the mixing assembly, and a valve assembly. The mixing assembly serves to mix and agitate the materials provided in the interior through rotation of a plunger portion and a spring attached thereto, and through upwards and downwards movement of the plunger portion in the interior area. Rotation of the crank assembly serves to rotate the plunger portion and the spring attached thereto, and effectuate upwards and downwards movement of the plunger portion. The valve assembly can be opened to facilitate dispensing of the materials from the interior area.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a manual mixer for use during surgery.More particularly, the present invention relates to a manual mixer formixing and agitating materials including liquids, pastes, and solidsadded thereto. More specifically, the present invention relates to amanual mixer for mixing and agitating materials through rotational andaxial movement of portions of a mixing assembly actuated by a crankassembly, and for dispensing the materials through a valve assembly viafurther actuation of the crank assembly.

Description of the Prior Art

Typically, materials such as liquids, pastes, and/or solids used duringsurgery must be prepared prior to their use. For example, many bonecements require mixing and agitation to prepare the cements for use inpatients. Oftentimes, the active ingredients need to be activated viamixing/agitation of the materials during surgery. Otherwise, the bonecement, for example, could harden before it is needed during surgery.Therefore, there is a need for a mixer that allows for easy mixing andagitation of materials during surgery so that the active ingredients canbe activated. Such a mixer should be easy to manually operate, andprovide at least two mechanisms by which the materials can be mixed andagitated. Such a manual mixer should also afford easy dispensingtherefrom so that the materials mixed and agitated thereby can be easilyaccessed for use during surgery.

SUMMARY OF THE INVENTION

The present invention in one preferred embodiment contemplates a manualmixer for mixing and agitating materials for use during surgery, themanual mixer including a body portion having a sidewall portion definingan interior area; a mixing assembly provided in the interior area of thebody portion, the mixing assembly including a plunger portion and avariable-diameter spring, the plunger portion including at least oneseal for interfacing with the sidewall portion, and the plunger portionincluding a portion for securely engaging the spring, thevariable-diameter spring including a first end portion, a second endportion, and a coil extending between the first end portion and thesecond end portion thereof, the coil having a variable diameter, theplunger portion being adapted to move upwardly and downwardly within theinterior area; a cap portion attached to the sidewall portion of thebody portion, the cap portion enclosing the interior area of the bodyportion, and the cap portion including an aperture that is at leastpartially threaded; and a stem portion extending through thepartially-threaded aperture in the cap portion, the stem portion beinginterconnected with the plunger portion, and the stem portion being atleast partially threaded, where threads of the partially-threaded stemportion and threads of the partially-threaded aperture engage oneanother, and where rotation of the stem portion simultaneously rotatesthe plunger portion and spring, and moves the plunger portion upwardlyor downwardly within the interior area, the rotational movement of theplunger portion and variable-diameter spring, and upward and downwardmovement of the plunger portion serving to mix and agitate the materialsprovided in the interior area.

The present invention in another preferred embodiment contemplates amanual mixer for mixing and agitating materials for use during surgery,the manual mixer including a body portion including a sidewall portion,the sidewall portion defining an interior area, a portion of theinterior area receiving the materials to be mixed and agitated; aplunger portion provided in the interior area, the plunger portionincluding at least one seal for preventing the passage of the materialto be mixed and agitated, the plunger portion being moveable upwardlyand downwardly within the interior area from between a first positionand a second position, the first position being a maximum upwardposition of the plunger portion, and the second position being a maximumdownward position of the plunger portion; a variable-diameter springprovided in the interior area, the variable-diameter spring including afirst end, a second end, and a coil extending between the first end andthe second end, the first end of the variable-diameter spring beingconnected to the plunger portion, the spring being expanded when theplunger portion is moved upwardly within the interior area, and thespring being compressed when the plunger portion is moved downwardlywithin the interior area; and a cap portion for enclosing the interiorarea, the cap portion including an aperture therethrough that is atleast partially threaded; a stem portion extending through thepartially-threaded aperture in the cap portion, the stem portion beinginterconnected with the plunger portion, the stem portion being at leastpartially threaded, where threads provided in the aperture and on thestem portion engage one another, and wherein rotational movement of thestem portion simultaneously rotates the plunger portion and thevariable-diameter spring, and moves the plunger portion upwardly ordownwardly within the interior area due to the interaction between thethreads provided in the aperture and on the stem portion, the rotationalmovement of the plunger portion and variable-diameter spring, and upwardand/or downward movement of the plunger portion serving to mix andagitate the materials provided in the interior area.

The present invention in yet another preferred embodiment contemplates amethod of mixing and agitating materials using a manual mixer, themethod including providing the manual mixer having a body portion, amixing assembly, and a stem portion, the body portion defining aninterior area, the mixing assembly being provided in the interior area,and the stem portion being interconnected with a portion of the mixingassembly; removing the mixing assembly from the interior area; providingthe materials to be mixed and agitated in the interior area; replacingthe mixing assembly in the interior area; and rotating the stem portionto simultaneously rotate a plunger portion and a variable-diameterspring of the mixing assembly, and move the plunger portion upwardly ordownwardly within the interior area, the rotation of the plunger portionand the variable-diameter spring, and upwards and/or downwards movementof the plunger portion serving to mix and agitate the materials providedin the interior area.

These and other objects of the present invention will be apparent fromreview of the following specification and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a manual mixer according to the presentinvention;

FIG. 2 is a perspective assembly view of the manual mixer depicted inFIG. 1;

FIG. 3 is a front elevational view of the manual mixer depicted in FIG.1;

FIG. 4 is a side elevational view of the manual mixer depicted in FIG.1;

FIG. 5 is a top plan view of the manual mixer depicted in FIG. 1;

FIG. 6 is a cross-sectional view of the manual mixer of FIG. 1 showing amixing assembly thereof in upwardly deposed position; and

FIG. 7 is a cross-sectional view of the manual mixer of FIG. 1 showingthe mixing assembly thereof in a downwardly deposed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with one preferred embodiment of the present invention,and as depicted in FIGS. 1-7, a manual mixer 10 is provided for mixingand agitating materials for use during surgery.

In accordance with the present invention, the manual mixer 10 includes apedestal portion 12 and a body portion 14, and, as depicted in FIGS.1-4, 6, and 7, the body portion 14 depends upwardly from the pedestalportion 12. The body portion 14, as depicted in FIGS. 2, 6, and 7 ishollow and in part defines an interior 16 of the manual mixer 10 inwhich materials (including liquids, pastes, and/or solids) can be mixedand agitated prior to use during surgery or other medical procedure. Anexample of a material that can be mixed using the manual mixer 10 is abone cement such as polymethyl methacrylate (PMMA).

The body portion 14 includes a top opening 18 (FIG. 2), and is formed bya sidewall portion 20 and a base portion 22 (FIGS. 6 and 7), Thesidewall portion 20 and the base portion 22 can be unitarily formed withthe pedestal portion 12, and along with a cap portion 24, the sidewallportion 20 and the base portion 22 define the interior 16 of the manualmixer 10. The sidewall portion 20 can be substantially cylindrical, andthe interior 16 can correspondingly be substantially cylindrical.Furthermore, the sidewall portion 20 can include exterior markings formeasuring the volume of the materials provided in the interior 16.

As depicted in FIG. 2, the cap portion 24 can be removably attached tothe sidewall portion 20 to cover the top opening 18. For example, thesidewall portion 20 and the cap portion 24 can include mating threads orsnap-fit mechanism facilitating their attachment to one another.

A mixing assembly 26, as depicted in FIGS, 2, 6, and 7, is provided inthe interior 16, and a crank assembly 28 is used to actuate the mixingassembly 26. As discussed below, the mixing assembly 26 (via actuationof the crank assembly 28) can be used in mixing and dispensing of thematerials provided in the interior 16. Portions of the mixing assembly26 are configured to move upwardly and downwardly within the bodyportion 14. Furthermore, a valve assembly 30, as discussed below, can beused in dispensing the materials from the manual mixer 10.

As depicted in FIGS, 1 and 2, the crank assembly 28 includes a stemportion 32, a crank portion 34, and a handle portion 36, Furthermore, asdepicted in FIGS, 6 and 7, the stem portion 32 is fixedly attached tothe crank portion 34, and the handle portion 36 is rotatably attached tothe crank portion 34. Alternatively, the stem portion 32 can also beattached to the crank portion 34 and the handle portion 36 by integrallyforming the crank portion 34 and/or the handle portion 36 therewith.

The stem portion 32 is cylindrical, and the stem portion 32 includes acentral longitudinal axis. The stem portion 32 can be completely orpartially threaded. Threads 38 provided on the stern portion 32 can beused in facilitating movement of the mixing assembly 26. Furthermore,the threads 38 of the stem portion 32 can be used to fixedly attach thestem portion 32 to the crank portion 34, as well as to portions of themixing assembly 26. As depicted in FIGS. 2, 6, and 7, threads 38 can beprovided on or adjacent a first end portion 40, and on or adjacent asecond end portion 42 thereof. To fixedly attach the stem portion 32 tothe crank portion 34, a threaded aperture can be provided in the crankportion 34 to receive the threads 38 provided on the first end portion40 of the stem portion 32. Alternatively, as depicted in FIGS. 6 and 7,a nut 44 can be press fit into an aperture 46 formed in the crankportion 34, and the threads 38 provided on the first end portion 40 canbe received in the nut 44 to fixedly attach the stem portion 32 and thecrank portion 34 to one another.

The stem portion 32 extends through an aperture 50 in the cap portion24. The aperture 50 can be formed by a threaded cylindrical sidewall 52for engaging the threads 38 provided on the stem portion 32. Theinteraction between the threads 38 provided on the stem portion 32 andthe threaded cylindrical sidewall 52 can facilitate rotational and axialmovement of the stern portion 32 within the aperture 50. Using the crankportion 34 and the handle portion 36, the stem portion 32 can be rotatedabout its central longitudinal axis within the aperture 50. Suchrotational movement would be translated into axial movement by theinteraction of the threads 38 provided on the stem portion 32 and thethreaded cylindrical sidewall 52. As discussed below, rotation of thestem portion 32 (by the crank portion 34 and the handle portion 36)serves to rotate portions of the mixing assembly 26, and thecorresponding axial movement of the stem portion 32 serves to moveportions of the mixing assembly 26 upwardly and downwardly within thebody portion 14. Such rotational and axial movement serves to mix thematerials provided in the interior 16, and can also, as discussed below,be used in dispensing the materials from the manual mixer 10. The pitchof the threads 38 and the threaded cylindrical sidewall 52 can bealtered to speed up or slow down the axial movement of the stem portion32.

Alternatively, the stem portion 32 and the aperture 50 can benon-threaded, such that the stem portion 32 can be freely rotated andmoved axially (upwardly and downwardly) relative to the aperture 50using the crank portion 34 and the handle portion 36. Such rotationaland axial movement can be used in mixing materials provided in theinterior 16, and can also, as discussed below, be used in dispensing thematerials from the manual mixer 10.

The mixing assembly 26, as depicted in FIGS. 2, 6, and 7, includes aplunger 60, a plunger adaptor 62, and a spring 64. As discussed below,the plunger 60 serves in part as a seal for containing the materialsbetween a lower portion 66 of the plunger 60 and the base portion 22 ofthe body portion 14. Furthermore, the plunger adaptor 62 engages theplunger 60 and is fixedly attached to the stem portion 32.Alternatively, rather than being separate components, the plunger 60 andthe plunger adaptor 62 can be integrally formed with one another. Tofixedly attach the stem portion 32 to the plunger adaptor 62, a threadedaperture can be provided in the plunger adaptor 62 to receive thethreads 38 provided on the second end portion 42 of the stem portion 32.Alternatively, as depicted in FIGS. 6 and 7, a nut 70 can be press fitinto an aperture 72 formed in the plunger adaptor 62, and the threads 38formed on the second end portion 42 can be received in the nut 70 tofixedly attach the stem portion 32 and the plunger adaptor 62 to oneanother. Because the plunger adaptor 62 is fixedly attached to the stemportion 32, rotational and axial movement of the stem portion 32 causesthe plunger 60 and the plunger adaptor 62 to rotate and move axially(i.e., upwardly and downwardly) within the body portion 14.

The plunger 60 includes the lower portion 66, a conical portion 74, andvarious rib portions 76. As discussed below, the conical portion 74includes an air release valve 78 allowing passage of air thereby, andthe rib portions 76 facilitate engagement of the plunger 60 to theplunger adaptor 62. Furthermore, the lower portion 66 includes a firstseal ring 80, a second seal ring 82, a connecting ring 84, and a flangeportion 86. As discussed below, the first seal ring 80 and the secondseal ring 82 serve as seals, the connecting ring 84 connects the firstseal ring 80 and the second seal ring 82 to one another, and the flangeportion 86 is configured to hold a portion of the spring 64.

As depicted in FIG. 2, the plunger adaptor 62 is substantiallycylindrical. The plunger adaptor 62 includes a top portion 90, asidewall portion 92, and an inner chamber 94 formed by the sidewallportion 92. The aperture 72 is formed in the top portion 90.Furthermore, the sidewall portion 92 is substantially cylindrical, andincludes various slits 96 for receiving the rib portions 76.Furthermore, the inner chamber 94 is sized to receive the conicalportion 74 and the rib portions 76 therein. The plunger 60 and theplunger adaptor 62 are attached to one another, when the rib portions 76are inserted in the slits 96, and the conical portion 74 and the ribportions 76 are received in the inner chamber 94.

The present invention provides a plunger 60 which helps move materialsthrough the body portion 14. In some embodiments, the plunger cancomprise an 0-ring gland or other suitable means of closing off apassageway to prevent unwanted loss of cement. As discussed above andrepresented in FIG. 2, the lower portion 66 of the plunger 60 serves inpart as a seal for containing the materials. In doing so, the exteriorperimeters of the first seal ring 80 and the second seal ring 82 contactthe inner surface of the sidewall portion 20. The exterior perimeters ofthe first seal ring 80 and the second seal ring 82 can be annular toconform to the cylindrical shape of the sidewall portion 20. Theconnecting ring 84 connects and spaces apart the first seal ring 80 andthe second seal ring 82. The first seal ring 80 and the second seal ring82 remain in contact with the inner surface of the sidewall portion 20as the plunger 60 moves in the body portion 14, and such contactinhibits the passage of the materials thereby.

The spring 64, as depicted in FIGS. 2, 6, and 7, includes a first endportion 100, a second end portion 102, and a coil 104 extending betweenthe first end portion 100 and the second end portion 102. The lowerportion 66 also serves in part for securely engaging the spring 64. Asdiscussed above, the lower portion 66 of the plunger 60 includes theflange portion 86. The flange portion 86 is configured to hold the firstend portion 100 of the spring 64 to facilitate attachment thereof to theplunger 60. The second end portion 102 of the spring 64 is not attachedto the body portion 14. Instead, given the length of the coil 104, thesecond end portion 102 is contacted with the inner surface of the baseportion 22. The second end portion 102 remains in contact with the innersurface of the base portion 22 as the plunger 60 and the plunger adaptor62 move upwardly and downwardly within the body portion 14.

As depicted in FIGS. 2, 6, and 7, the coil 104 of the spring 64 has avariable diameter. Unlike a spring having a coil of uniform diameter,the parts of the coil 104 do not fully stack upon one another as thespring 64 is compressed. Thus, when fully compressed, the spring 64 hasa lesser height than a spring having a uniform diameter. As such, theplunger 60 and plunger adaptor 62 can travel farther downwardly withinthe body portion 14 with use of the spring 64 that has a variablediameter, than with use of a spring that has a uniform diameter.

As discussed above, the spring 64 is attached to the plunger 60. Thus,as the plunger 60 and plunger adaptor 62 rotate and move axially (i.e.,upwardly and downwardly) within the body portion 14, the spring 64 isrotated and correspondingly expanded or compressed. The rotation andexpansion/compression of the spring 64 serves to mix and agitate thematerials provided in the interior 16. The plunger 60 is moveablebetween an upward position (FIG. 6) and a downward position (FIG. 7).Additionally, the downward axial movement of the plunger 60 serves tocompress the materials provided in the interior 16. The compressionthereof can force the materials to exit the manual mixer 10 through thevalve assembly 30. By exiting through the valve assembly 30, thematerials can be dispensed from the manual mixer 10.

The valve assembly 30 includes a valve body portion 110, a handle/plugportion 112, and a connecting portion 114. The valve body portion 110includes an outlet 116, and the valve body portion 110 receives portionsof the handle/plug portion 112. The handle plug/portion 112 includes twohandles 118, a plug 120, and a plug port 122. The handles 118 allow forambidextrous operation of the valve assembly 30. The plug 120 extendsthrough the valve body portion 110, one of the handles 118 is integrallyformed with the plug 120, and the other of the handles is fixedlyattached to the plug 120.

The connecting portion 114 can be used to attach the valve assembly 30to the sidewall portion 20 of the body portion 14. The connectingportion 114 include two arm portions 124 for engaging two tabs 126provided on the sidewall portion 20.

The plug port 122 can be rotated into and out of communication with theoutlet 116 and an outlet port 130 formed though the body portion 14using either of the handles 118. When the plug port 122 is in the closedposition, the materials in the interior 16 are prevented from exitingthe manual mixer 10 through the outlet 116. When the plug port 122 is inthe opened position, the materials are permitted to exit the the manualmixer 10 through the outlet 116. Thus, with the plug port 122 in theopened position, the materials are dispensed through the outlet 116 whenthe plunger 60 is moved downwardly (via actuation of the crank assembly28).

During use of the manual mixer 10, the materials to be mixed andagitated thereby can be added to the interior 16 for mixing andagitation by first removing the cap portion 24, the mixing assembly 26,and the crank assembly 28 from the remainder of the manual mixer 10.With the cap portion 24, the mixing assembly 26, and the crank portion28 removed from the manual mixer 10, the materials to be mixed andagitated can be added to the interior 16 through the top opening 18 ofthe body portion 14. After the materials are added to the interior 16,the cap portion 24, the mixing assembly 26, and the crank assembly 28can be replaced onto the remainder of the manual mixer 10.

When the materials to be mixed/agitated are provided in the interior 16,the cap portion 24, the mixing assembly 26, and the crank assembly 28are in position, and the plug port 122 is in the closed position, thecrank assembly 28 can be actuated to actuate the mixing assembly 26. Asdiscussed above, rotation of the crank portion 34 rotates the stemportion 32, and rotation of the stem portion 32 serves to rotate theplunger 60 and spring 64, as well as serves to move the plunger 60axially upwardly and downwardly to expand and compress the spring 64,respectively. Rotation of the crank portion 34 in one direction can thusrotate the spring 64, and move the plunger 60 downwardly to compress thespring 64. Such rotational and axial movement mixes and agitates thematerials. Furthermore, with the plug port 122 rotated into the openposition, further downward movement of the plunger 60 can compress thematerial, thereby forcing the materials to be dispensed out of theinterior 16 through the valve assembly 30. A syringe 132, as depicted inFIGS. 1, 6, and 7, can be attached to the valve assembly 30 can befilled as the materials are dispensed from the manual mixer 10.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

I/We claim:
 1. A manual mixer for mixing and agitating materials for useduring surgery, the manual mixer comprising: a body portion having asidewall portion defining an interior area; a mixing assembly providedin the interior area of the body portion, the mixing assembly includinga plunger portion and a variable-diameter spring, the plunger portionincluding at least one seal for interfacing with the sidewall portion,and the plunger portion including a portion for securely engaging thespring, the variable-diameter spring including a first end portion, asecond end portion, and a coil extending between the first end portionand the second end portion thereof, the coil having a variable diameter,the plunger portion being adapted to move upwardly and downwardly withinthe interior area; a cap portion attached to the sidewall portion of thebody portion, the cap portion enclosing the interior area of the bodyportion, and the cap portion including an aperture that is at leastpartially threaded; and a stem portion extending through thepartially-threaded aperture in the cap portion, the stem portion beinginterconnected with the plunger portion, and the stem portion being atleast partially threaded, wherein threads of the partially-threaded stemportion and threads of the partially-threaded aperture engage oneanother, and wherein rotation of the stem portion simultaneously rotatesthe plunger portion and spring, and moves the plunger portion upwardlyor downwardly within the interior area, the rotational movement of theplunger portion and variable-diameter spring, and upward and downwardmovement of the plunger portion serving to mix and agitate the materialsprovided in the interior area.
 2. The manual mixer of claim 1, furthercomprising a crank assembly, the crank assembly including the stemportion, a crank portion, and a handle portion, the crank portion beingconnected to the stem portion, and the handle portion being connected tothe crank portion, wherein rotation of the crank portion and the handleportion imparts rotational movement to the stem portion.
 3. The manualmixer of claim 1, wherein the variable-diameter spring is expanded whenthe plunger portion is moved upwardly, and the variable-diameter springis compressed when the plunger portion is moved downwardly.
 4. Themanual mixer of claim 3, wherein the variable-diameter spring has amaximum diameter and a minimum diameter, the maximum diameter beinggreater than the minimum diameter, the variable-diameter spring, whenfully compressed, having a substantially smaller height than a springhaving a uniform diameter equal to the maximum diameter.
 5. The manualmixer of claim 1, further comprising a valve assembly, wherein the bodyportion includes an outlet port communicating with the valve assembly,the valve assembly including a plug movable between an open positionpermitting fluid communication through the valve assembly between theoutlet port and the exterior of the manual mixer, and a closed positionprohibiting fluid communication through the valve assembly between theoutlet port and the exterior of the manual mixer.
 6. The manual mixer ofclaim 5, wherein downward movement of the plunger portion compresses thematerials provided in the interior area, and, when the plug of the valveassembly is in the open position, the compression of the materials viadownward movement of the plunger portion forces the materials to exitthe manual mixer through the outlet port and the valve assembly.
 7. Themanual mixer of claim 6, wherein the plunger portion includes an airrelease valve allowing the passage of air thereby during compression ofthe materials in the interior area.
 8. The manual mixer of claim 1,wherein the materials mixed and agitated by the manual mixer includebone cement.
 9. A manual mixer for mixing and agitating materials foruse during surgery, the manual mixer comprising: a body portionincluding a sidewall portion, the sidewall portion defining an interiorarea, a portion of the interior area receiving the materials to be mixedand agitated; a plunger portion provided in the interior area, theplunger portion including at least one seal for preventing the passageof the material to be mixed and agitated, the plunger portion beingmoveable upwardly and downwardly within the interior area from between afirst position and a second position, the first position being a maximumupward position of the plunger portion, and the second position being amaximum downward position of the plunger portion; a variable-diameterspring provided in the interior area, the variable-diameter springincluding a first end, a second end, and a coil extending between thefirst end and the second end, the first end of the variable-diameterspring being connected to the plunger portion, the spring being expandedwhen the plunger portion is moved upwardly within the interior area, andthe spring being compressed when the plunger portion is moved downwardlywithin the interior area; a cap portion for enclosing the interior area,the cap portion including an aperture therethrough that is at leastpartially threaded; and a stem portion extending through thepartially-threaded aperture in the cap portion, the stem portion beinginterconnected with the plunger portion, the stem portion being at leastpartially threaded, wherein threads provided in the aperture and on thestem portion engage one another, and wherein rotational movement of thestem portion simultaneously rotates the plunger portion and thevariable-diameter spring, and moves the plunger portion upwardly ordownwardly within the interior area due to the interaction between thethreads provided in the aperture and on the stern portion, therotational movement of the plunger portion and variable-diameter spring,and upward and/or downward movement of the plunger portion serving tomix and agitate the materials provided in the interior area.
 10. Themanual mixer of claim 9, further comprising a crank assembly, the crankassembly including the stem portion, a crank portion, and a handleportion, the crank portion being connected to the stern portion, and thehandle portion being connected to the crank portion, wherein rotation ofthe crank portion and the handle portion imparts rotational movement tothe stem portion.
 11. The manual mixer of claim 9, wherein thevariable-diameter spring has a maximum diameter and a minimum diameter,the maximum diameter being greater than the minimum diameter, thevariable-diameter spring, when fully compressed, having a substantiallysmaller height than a spring having a uniform diameter equal to themaximum diameter.
 12. The manual mixer of claim 9, further comprising avalve assembly, wherein the body portion includes an outlet portcommunicating with the valve assembly, the valve assembly including aplug movable between an open position permitting fluid communicationthrough the valve assembly between the outlet port and the exterior ofthe manual mixer, and a closed position prohibiting fluid communicationthrough the valve assembly between the outlet port and the exterior ofthe manual mixer.
 13. The manual mixer of claim 12, wherein downwardmovement of the plunger portion compresses the materials provided in theinterior area, and, when the plug of the valve assembly is in the openposition, the compression of the materials via downward movement of theplunger portion forces the materials to exit the manual mixer throughthe outlet port and the valve assembly.
 14. The manual mixer of claim13, wherein the plunger portion includes an air release valve allowingthe passage of air thereby during compression of the materials in theinterior area.
 15. The manual mixer of claim 9, wherein the materialsmixed and agitated by the manual mixer include bone cement.
 16. A methodof mixing and agitating materials using a manual mixer, the methodcomprising: providing the manual mixer having a body portion, a mixingassembly, and a stem portion, the body portion defining an interiorarea, the mixing assembly being provided in the interior area, and thestem portion being interconnected with a portion of the mixing assembly;removing the mixing assembly from the interior area; providing thematerials to be mixed and agitated in the interior area; replacing themixing assembly in the interior area; and rotating the stem portion tosimultaneously rotate a plunger portion and a variable-diameter springof the mixing assembly, and move the plunger portion upwardly ordownwardly within the interior area, the rotation of the plunger portionand the variable-diameter spring, and upwards and/or downwards movementof the plunger portion serving to mix and agitate the materials providedin the interior area.
 17. The method of claim 16, wherein the plungerportion is moveable between a first position and a second position, thefirst position being a maximum upward position of the plunger portion,and the second position being a maximum downward position of the plungerportion, the variable-diameter spring being expanded when the plungerportion is moved upwardly within the interior area toward the firstposition, and the variable-diameter spring being compressed when theplunger portion is moved downwardly within the interior area toward thesecond position.
 18. The method of claim 16, wherein thevariable-diameter spring has a maximum diameter and a minimum diameter,the maximum diameter being greater than the minimum diameter, thevariable-diameter spring, when fully compressed, having a substantiallysmaller height than a spring having a uniform diameter equal to themaximum diameter.
 19. The method of claim 16, wherein the manual mixerincludes a valve assembly, and the body portion includes an outlet portcommunicating with the valve assembly, the valve assembly including aplug movable between an open position permitting fluid communicationthrough the valve assembly between the outlet port and the exterior ofthe manual mixer, and a closed position prohibiting fluid communicationthrough the valve assembly between the outlet port and the exterior ofthe manual mixer.
 20. The method of claim 19, wherein downward movementof the plunger portion compresses the materials provided in the interiorarea, and, when the plug of the valve assembly is in the open position,the compression of the materials via downward movement of the plungerportion forces the materials to exit the manual mixer through the outletport and the valve assembly.